Convergence yoke apparatus for color television receiver

ABSTRACT

In a convergence yoke apparatus for color television receivers comprising two magnetic cores, one of the cores cooperating with an electron gun B and the other with electron guns R and G contained in a color cathode-ray tube, the other core is formed to have a letter E configuration, horizontal and vertical coils are wound upon two outer legs of the E-shaped core and a compensation coil is wound on the central leg.

United States Patent 1 3,611,221

[7 2 inventor l-liroshi lkeuchi [5 6] References Cited [21] A l N g gg UNITED STATES PATENTS pp o. Filed g 1970 3,534,208 10/1970 Kruckhaudt et al. 313/77 [45] Patented Oct. 5, 1971 Primary Examiner-J. V. Truhe [73] Assignee Dcnki Onltyo Company, Limited Assistant Examiner.l. G. Smith Tokyo, Japan A1l0rneyChittick, Pfund, Birch, Samuels & Gauthier [32] Priority Aug. 15, 1969 [33] Japan I 31 44/77277 ABSTRACT: In a convergence yoke apparatus for color CONVERGENCE YOKE APPARATUS FOR COLOR television receivers comprising two magnetic cores, one of the TELEVISION RECEIVER 1 Claim 2 Drawing a cores cooperating Wllh an electron gun B and the other with electron guns R and 0 contained in a color cathode-ray tube.

[52] U.S.Cl 335/212 the other core is formed to have a letter E configuration. [51 Int. Cl H01! 1/00 horizontal and vertical coils are wound upon two outer legs of [50] Field of Search 335/2l2; the E-shaped core and a compensation coil is wound on the 313/76, 77 central leg.

PATENTEDHBT 5197i 361 1.221

FIG. I

PRIOR ART FIG. 2

INVENTOR HIRO'SHI IKEUCHI BY I CONVERGENCE YOKE APPARATUS FOR COLOR TELEVISION RECEIVER BACKGROUND OF THE INVENTION brevity, two types of coils are shown as a single coils) and the outer ends of two legs of the core 2 are disposed to oppose pole pieces of electron gun B. On the other hand, convergence core 3 is utilized in common for red and green electron guns R and G and is also provided with horizontal and vertical coils L on its two legs. With this type of the convergence apparatus when the cathode-ray tube and deflection coils are constructed perfectly the convergence operation is performed theoretically. However due to inaccuracies in the cathode-ray tube and deflection coils it is not always possible to obtain satisfactory results. In order to magnetically compensate for such inaccuracies a compensation coil L wound about two legs of the core 3 has been used as is well known in the art. Assuming now that coils L and L are excited to produce fluxes 1 and as shown in FIG. I, in the field region of electron gun G fluxes d and D add each other whereas in the field region of electron gun R these fluxes subtract from each other. By adjusting the field intensity in this manner, it is possible to provide the desired compensation. As can be noted from FIG. I, in theprior art apparatus, flux 1 produced by compensation coil L flows upwardly after passing through pole pieces of electron guns G and R. This means increased magnetic reluctance for flux d1, thus decreasing the ability of the dynamic convergence.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved convergence yoke for use in color television receivers capable of reducing the reluctance for the flux produced by the compensation coil thus improving the efficiency of the dynamic convergence.

According to this invention magnetic core 3 is modified to take the form of a letter E. The horizontal and vertical coils L are wound on two outer legs of the core opposing pole pieces of electron guns R and G respectively and the compensation coil is wound on the center leg of the core. This arrangement greatly reduces the magnetic reluctance for the flux produced by the compensation coil thus increasing the efficiency of the dynamic convergence.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing:

FIG. 1 is a diagrammatic representation, partly in section, of the prior art convergence yoke apparatus and FIG. 2 is a similar view of the convergence yoke apparatus embodying this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now to FIG. 2, like the arrangement shown in FIG. 1, a C-shaped core 2 has two legs opposing the pole pieces of an electron gun B and horizontal and vertical coils L, wound upon two legs and functions to converge the beam emanated from gun B. According to this invention the convergence function for electron beams emanated from electron guns R and G is provided by a single letter E shaped core 4 having three legs. Two outer legs 41 and 42 of the core carry horizontal and vertical coils L to produce convergence flux I while central leg 43 carries t compensation coil L, for producing flux D In the field region of the electron gun R fluxes 1 and Q add each other while in the field region of electron gun G, these fluxes subtract from each other, thus providing the desired compensation effect. It is to be particularly noted that since flux D flows through two paths, each starting from the central leg 43 and returning to respective outer legs 41 and 42 respectively through pole pieces of electron guns G and R it is possible to greatly reduce the reluctance to flux D when compared with the prior arrangement shown in FIG. 1. As diagrammatically shown in FIG. 2, magnetic members 5 and 6 are provided to decrease the mag netic reluctance between two outer legs of the core 4 and the pole pieces of electron guns R and G. However these magnetic members may be omitted if outer legs 41 and 42 are extended close to the wall of the neck 1 of the cathode-ray tube.

Thus, according to this invention the convergence core for electron guns R and G is formed to have a letter E configuration and a compensation coil is wound on the central leg of the core thus greatly reducing the reluctance to the flux generated by the compensation coil and thus increasing the dynamic convergence effect.

While the invention has been shown and described in terms of the preferred embodiment thereof various changes and modifications will occur to one skilled in the art without departing from the true spirit and scope of the invention as defined in the appended claim.

What is claimed is:

1. In convergence yoke apparatus for use in a color television cathode-ray tube of the type including two magnetic cores cooperating with electron guns contained in said cathode-ray tube the improvement which comprises a letter C shaped magnetic core with two legs opposed to the pole piece of an electron gun for emanating an electron beam for blue, said legs carrying horizontal and vertical coils, a letter E shaped magnetic core, two outer legs of said E-shaped core carrying horizontal and vertical coils and opposing pole pieces of electron guns emanating electron beams for red and green. and a compensation coil wound upon the central leg of said E- shaped core.

a UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 611 221 Dated OctoQe: 5 I 1,2 21

Inventor f Hiroshi Ikeuchi It: is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 14, change "coils" to coil Colunm 1, line 29, before "each" insert to Column 2, line 16, delete "t" and insert a Signed and sealed this 25th day of April 1972.

(SEAL) Attest':

EDWARD PLFLETCHER, JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. In convergence yoke apparatus for use in a color television cathode-ray tube of the type including two magnetic cores cooperating with electron guns contained in said cathode-ray tube the improvement which comprises a letter C shaped magnetic core with two legs opposed to the pole piece of an electron gun for emanating an electron beam for blue, said legs carrying horizontal and vertical coils, a letter E shaped magnetic core, two outer legs of said E-shaped core carrying horizontal and vertical coils and opposing pole pieces of electron guns emanating electron beams for red and green, and a compensation coil wound upon the central leg of said E-shaped core. 